Second environment safety for projectiles

ABSTRACT

A LOW MASS ELEMENT CARRIED BY A PROJECTILE AND RESPONSIVE TO AERODYNAMIC DRAG FOR PROVIDING A SECOND ENVIRONMENT SAFETY TO A PROJECTILE FUSING SYSTEM WHICH INCORPORATES AN INTEGRATING ACCELEROMETER AS A PRIMARY SAFETY IN ARMING OF THE FUSE SUBSEQUENT TO PROJECTILE FIRING.

3 Sheets-Sheet 1 INVENTOR CHRISTE M. SHEKRO hay! ATTORNEY.

Q. M. SHEMRQ Nov M, NH

sEGOND muvmommmrr SAFETY FOR PROJEQTILES Filed Aug. 14, 1968 A m @m Nov. 16, 1971 m. M. smmw 3,620,163

SECOND ENVIRONMENT SAFETY FOR PROJECTILES Filed Aug. 14, 1968 3 Sheets-Sheet 3 VELOCITY DISTANCE DISTANCE VELOCITY* ACCELERATION ARMING TIME INVENTOR CHRISTIE M. SHEKRO ATTOR NEY5.

Nov. 16, 1971 mm. SHEKRO 3,620,163

SECOND ENVIRONMENT SAFETY FOR PROJECTILES Filed Aug. 14. 1968 a Sheets-Sheet 5 INVENTOR CHRISTE M SHEKRO way, W JQ y- ATTOR NEYS.

FIG. 5

United States Patent US. Cl. 102-78 17 Claims ABSTRACT OF THE DISCLOSURE A low mass element carried by a projectile and responsive to aerodynamic drag for providing a second environment safety to a projectile fusing system which incorporates an integrating accelerometer as a primary safety in arming of the fuse subsequent to projectile firing.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to projectiles of the free falling or propelled type such as high speed rockets and more particularly, to such projectiles which employ an integrating accelerometer for delay arming of the projectile fuse.

The prior art Fired projectiles, free falling bombs and the like are normally detonated in the area of the target as a result of point detonation due to projectile impact with an object, time detonation by a suitable timer carried by the projectile itself, or proximit detonation involving means sensing a particular environment surrounding the moving projectile at any given moment.

To provide safety during transportation and handling of bombs and projectiles, various means are used to assure that fuse arming does not occur until the bomb or projectile senses its proper environment during a successfully executed launch. The probability of premature detonation using conventional fusing systems is extremely low, although they do occur and the need for even safer fusing systems is apparent.

There has been in use for a considerable period of time, projectile fusing systems employing the so-called S and A device which consists of an integrating accelerometer which arms the projectile after it has traveled a safe distance S from the point of release or firing. The distance S is determined by effectively taking the double integration of acceleration. The acceleration sensitive means, such as a rotor, after firing rotates in response to acceleration from an inoperative to an operative position in which arming of the projectile is achieved. Once the fusing system is armed, the basic detonating device such as a movable firing pin for point or impact detonation, a timer for time detonation and a sensing mechanism for proximity detonation takes over. Thus, the detonating device acts in conjunction with the S and A device of the fusing system.

SUMMARY OF THE INVENTION The present invention is directed broadly to a fusing system which employs a device which senses an environment other than the acceleration-time environment of the S and A device. The invention is further directed to the employment of the second environment sensing device acting in conjunction with the S and A device to insure maximum safety in the firing of the projectile. In particular, the second environment device of the present invention is responsive to the aerodynamic drag force acting on the moving projectile which is a function of projectile velocity.

As such, the projectile fusing system broadly includes an integrating accelerometer carrying a detonator charge which is movable from a first, inoperative position with respect to the warhead charge to a second, operative or detonating position relative thereto. The improvement comprises a movable, lightweight second environment sensing member carried by the projectile which is subject to the aerodynamic drag force during fiight and is biased to a first position. Means are operatively coupled to the lightweight member for isolating the accelerometer carried detonator charge from the warhead or booster charge when the lightweight member is in the first position in the absence of a projectile velocity, and hence drag force, sufficient to overcome the bias force. Regardless therefore, of the operation of the S and A device, the fusing system remains safed until the velocity of the projectile increases to the point where the aerodynamic drag force moves the lightweight member to the second position to operatively connect the detonator charge carried by the accelerometer with the warhead charge carried by the projectile proper.

In a preferred form, the lightweight second environment member comprises a low mass, axially shiftable nose cone which is spring biased to a forward position. The accelerometer comprises a rotatable member bored to carry a primer and detonator charge in axial alignment with the bore, prior to firing, being misaligned with the warhead charge or booster and isolated by a cam biased slider positioned intermediate of these members. The slider, in response to axial shifting of the conical nose against the bias of its spring, is cammed to a second position to expose the axially aligned detonator charge to the warhead or booster charge.

In an alternate embodiment, a detent mechanism locks the cam operated slider in the armed position in response to a predetermined projectile velocity. In yet another embodiment a rotary drive lever responsive to completed travel of the rotary S and A device, locks the slider in the safed position to prevent subsequent actuation of the second environment safety if the S and A device completes its travel prior to drag actuation of the slider, and locks the slider in armed position if the second environment slider is moved to the armed position prior to completion of S and A rotor movement.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional, plan view of a detonating fuse incorporating the second environmental safety of the present invention, prior to firing of the projectile.

FIG. 2 is the same view of the fuse as FIG. 1 subse quent to projectile firing and arming.

FIG. 3 is a plot of the typical fiight characteristics of a projectile incorporating a second environment safety fuse system of the present invention.

FIG. 4 is a sectional, plan view of a detonating fuse forming a second embodiment of the present invention.

FIG. 5 is a sectional, plan view of a detonating fuse forming yet another embodiment of the present invention, prior to projectile firing.

FIG. 6 is the same view as FIG. 5 of the fuse after firing and arming.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a point detonating (impact) fuse It) incorporates the second environment safety device of the present invention and may be employed with rocket munitions and the like. As such, the point detonating fuse 10 is dependent upon velocity and acceleration of the projectile (not shown) which carries the fuse at the forward end thereof. Of course, the concept of the present invention may be applied equally as well to proximity-actuated fuses and also to time actuated fuses. The fuse It) incorporates a cylindrical casing 12 which carries in conventional fashion, a first firing pin 14 slidably positioned within bore 16 at the forward end of the fuse inner body 18. A large cavity 20 is formed within inner body 18, at the rear of the firing pin 14, the cavity 20 carrying a conventional S and A (safety and arming) device 21. A sector rotor 22 is mounted for pivotable rotation about an axis 24 (by means not shown) and carries an elongated bore 26 which passes through the axis of rotation and extends completely through the rotor. Bore 26 carries a primer charge 28 at its forward end and a detonator charge 30 at the rear. In conventional fashion, in response to acceleration, the sector rotor 22 pivots about axis 24 from the position shown in FIG. 1 to the position shown in FIG. 2. In this position, bore 26, and detonator charges 28 and 30 respectively are axially aligned with the firing pin 14. The tapered point 32 of the firing pin is in line with the center of the primer charge 28 and spaced slightly therefrom. A wall 34 extends transversely across the rear of the cavity 20. Wall 34 includes a central opening 36 which is axially aligned with detonator charge 30 after the rotor 22 has shifted on a time-acceleration basis from the initial position shown in FIG. 1 to the position shown in FIG. 2.

Conventionally, a booster charge or the warhead charge itself would be carried behind the transverse wall 34 within cavity 38 and exposed to the detonator charge 30 so that upon firing of the same, the main charge of the projectile warhead would be detonated. Fuse 10 is threadably coupled to the front of the projectile carrying the warhead charge.

The safety and arming device 21 functions as an integrating accelerometer which measures the product off acceleration and time; that is, it responds to an acceleration-time environment. Proper sensing of this environment results in rotation of the S and A rotor 22 through the angle A to its final, armed position. At this point, the rotor is locked by means including the small hole 40 which is drilled into the face of the rotor 22 and which, is aligned with the firing pin 14 prior to firing. On rotation, as indicated in FIG. 2, the small hole moves to a position opposite side wall 42 of cavity 20 and means (not shown) locks rotor 22 in position, with the charges 28 and 30 being aligned with the central axis of the fuse. The S and A device of the present invention thus operates in its normal mode in the exact manner as the prior art.

The second environment sensing and actuation safety device of the present invention is indicated generally at 44 and comprises a nose member 46 of lightweight construction integral with elongated cylindrical shell or casing portion 49 which overlies inner body 18 and its integral casing 12. In this respect, the inner body 18 has its periphery reduced at 50, at its forward end, to form a right angle shoulder 52 rearwardly of its conical nose. Casing 12 is further provided with a partial circumferential recess 54,

while, the cylindrical portion 48 of modified nose 46 is provided with an annular, inwardly directed radial protrusion 56, having a grooved inner surface 58 which carries O-ring seal 60. A coil spring 62 is positioned within the space 64 formed by the peripherally reduced portion and cylindrical section 48 of the nose. Further, with an axial gap 66 formed between the rear surface 68 of the nose and a front surface of inner body 18, the nose 46 and cylindrical portion may shift axially against the bias of the coil spring 62.

Cylindrical portion 48 carries an integral cam 70 which is received within recess 54 and has a tapered cam surface 72, upon which rides, a transversely movable cam follower or slider 74. In this respect, a second transverse wall member 76 extends parallel to transverse rear wall member 34 and is spaced therefrom to define slider cavity 78 which receives slider 74. Slider 74 is provided with a hole or opening 80 of similar diameter to opening 36 of wall 34 and an opening 82 carried by transverse wall 76. Opening 80 is intermediate of cam follower edge 84, at the outer end of the slider and follower inner end 86. A slider spring 88 is positioned within slider cavity 78 between the inner end 86 of the slider and a rear wall 87 forming the slider cavity. Thus, coil spring 88 biases the slider edge 84 in contact with the tapered cam surface '72 of cam member 70. Note further, that prior to flight, the axis of hole 80 is offset from the aligned axis of holes 36 and 82 carried by the wall members 34 and 76. In fact, side walls 90 and 92 of the slider block off the path between the detonator charge 40 and the booster charge (not shown) carried by cavity 38 of the fuse, in the absence of transverse shifting of the slider in response to cam operation. In order to prevent contamination of the interior elements of the fuse 10, there is provided in addition to the O-ring 60, a thin annular plastic sheet having one end 96 fixed to casing 12 and the other end 98 coupled to the outer surface of cylindrical portion 48.

The operation of a projectile such as a rocket carrying the fuse of the present invention may be best understood by reference to FIG. 3 which is a plot of the typical flight characteristics of a fuse incorporating a second environmental safety. As the rocket or projectile carrying the fuse is accelerated through the air, its velocity increases rapidly. The distance traveled by the projectile is also indicated with all three parameters, velocity, distance and acceleration being plotted against time. As the aerodynamic drag force, operating on the vehicle and in particular the lightweight, nose 46, increases (varying as the square of velocity), the drag force is sufficient to compress coil springs 62 causing cam face 72 to ride on cam follower edge 84 of the follower. Thus, the movement of the nose is conveyed to the slider through inclined plane action moving the slider to the point where the slider hole 80 is in line with holes 36 and 82 carried by transverse wall members 34 and 76 respectively.

Further, if the S and A rotor 22 has rotated from the position shown in FIG. 1 to the position shown in FIG. 2, the slider hole 80 is also in axial alignment with hole or bore 26 of the safety and acceleration device rotor 22. Remembering that the safety and arming device rotates upon sensing acceleration over a given time, it is seen from FIG. 3, that the S and A arming time is normally in excess to that of the second environment safety arming time. This is achieved by proper design proportioning. At time T the nose 46 has moved rearwardly sufficiently to force cam slider 74 into hole alignment position. At a later time T the S and A arming device rotor 22 has moved from the position shown in FIG. 1 to the position shown in FIG. 2 with its bore 26 and the detonator charges 28 and 30 in axial alignment with the inner firing pin 14 and holes 36, 80 and 82 respectively. Thus, provided that the S and A device also functions properly and aligns its charges with the central axis, the second environmental responsive fuse becomes fully armed for detonation. In the present case point detonation is provided by outer firing pin 100 acting in conjunction with inner firing pin 14. Upon impact with the target by the nose 46, the firing pins 100 and 14 are sequentially driven, detonating primer charges 28 and 30, the load charge (if one is present) and the booster charge (not shown) within cavity 38 and finally the warhead (not shown). In the event that either of the two environments is absent the fuse is safed. During ground handling, in the event that the S and A device 21 becomes armed (somehow) and the projectile carrying the fuse is accidentally dropped on its nose, it remains safe since a suddenly applied shock force is resisted by a large reaction viscous damping force generated in the nose chamber by the O-ring seal 60 along with that provided by the plastic sheath 94.

The characteristics of the second environment arming system of the present invention will become apparent from the following discussion. To function properly, the second environment safety must be relatively non-responsive to reaction inertia forces caused by rocket motor acceleration (if used in this environment), but must be very responsive to aerodynamic drag forces. The first characteristic is achieved by proportioning the nose 46 and its cylinder portion 48 so that it is very light in weight and by making the bias coil spring 62 very stiff (high spring constant). As a result, deflection of the spring is negligible since the reaction force (mass times acceleration) applied to the spring is small.

The second characteristic is achieved from a determination of drag forces that will exist during projectile flight. The basic equation for aerodynamic drag force is as follows:

F kC dA V Where:

F equals the aerodynamic drag force,

k equals a constant of proportionality,

C is the coetficient of drag,

d is the density of air,

A is the cross sectional area of the nose,

V is the velocity of the rocket relative to air.

For a given cross-sectional area A projected to the wind stream, the drag force depends basically upon the velocity squared. Hence, the spring constant may be selected as to be compatible with the velocity (and hence drag force) at any point in the trajectory. That is, full spring deflection which actuates the slider to the armed position can be achieved at any time point desired. In the present application, a time point prior to arming by the S and A device 21 has been selected.

As the rocket is launched, its initial velocity V may be zero if it is launched from a hovering helicopter, or it may be near Mach I if launched from a high performance aircraft (or any velocity in between these two points). The period of acceleration will provide a boost velocity up to burnout of the rocket motor. To accommodate these two widely separated velocity conditions, two different springs may be used, a softer spring for helicopter application and a stiffer spring for aircraft application.

From the above, it is seen that two independent environments must be sensed to their proper respective levels by separate devices operating independently before the fuse is on. Further, each device is capable of safing the fuse in the event its environment is not proper or nonexistent. This double environment fuse provides for greater safety features than a single environment fuse since two characteristics of successfully launched rockets must be sensed almost simultaneously or at close order and not necessarily in any prescribed sequence.

Referring next to FIG. 4, a second embodiment of the present invention is shown in conjunction with a fuse which is identical in construction to that of the device of FIGS. 1 and 2 with the exception that fuse 10 employs an additional detent mechanism to latch or lock the slider into fused position upon the projectile reaching a prescribed velocity as at time T in the flight characteristic plot of FIG. 3. With respect to the embodiment of FIG. 4, like elements of fuse 10 to the embodiment of FIGS. 1 and 2 will be given like numerical designations. Thus, fuse 10' includes inner body 18 and cylindrical casing section 12, slidably carrying a nose 46 and a thin wall casing section 48 with its integral cam 70. Tapered cam surface 72 acts on cam follower edge 84 of the slider 74 and again, the inner body firing pin 14 impacts primer charge 28 carried by bore 26 of the S and A device rotor 22, with the detonator charges 28 and 30 being, in axially aligned and exposed to slider hole 80 upon proper positioning of the slider 74. The slider 74, in addition to carrying axial hole 80, is also provided with a small diameter bore or hole 102 which extends partially through slider 74 from wall 90 and in a direction parallel to hole 80. The bore 102 is positioned intermediate hole 80 and the outer cam follower edge 84 of the slider. Further, a detent mechanism indicated generally at i104 is fixedly positioned within S and A cavity and consists of a cylindrical housing 106 carrying a slidable detent pin 108 which is spring biased towards the rear of the fuse by coil spring 110. In this respect, the transverse side wall 34 is bored at 112 to receive the projecting tip 114 of the detent pin and is counterbored at 116, partially through the thickness of the wall, to receive and locate the cylindrical detent casing 106. The tip 114 of the detent piston, is of a diameter slightly less than the diameter of bore 112 and bore 102 of slider '74.

In operation, the independent actuations of the first environment device 21 and the second environment device 44 are identical to that of the embodiment of FIGS. 1 and 2. However, in this case, regardless of the time T for the S and A arming device 21, once the velocity of the projectile reaches a value corresponding to time T FIG. 3, the cam 70 coupled to nose 46 will have moved slider 74 inwardly against the bias of slider spring 88 to a position where the slider hole is axially aligned with holes 36 and 82 carried by transverse side walls 34 and 76, respectively. There is also axial alignment between bore 102 of the slider 74 and the axis of the detent pin 108. The compression spring 110 forces the pin to the right, with the pin tip 114 being received within the bore 102 of the slider to maintain the slider in hole alignment position regardless of subsequent velocity conditions.

Basically, the acceleration and aerodynamic drag characteristics of the timing system of the second embodiment are identical with those of the first embodiment. With the addition of the detent mechanism 104, the second environment safety 44 becomes locked or detented in the armed position after the proper level of drag force is sensed by the nose 46. Again, while the detented first and second environment safety fusing system of the present invention is shown as applied to a point detonating fuse, the principles of the invention are equally applicable to fuses of the time detonating or proximity detonating type.

Referring next to FIGS. 5 and 6, a third embodiment of the present invention is shown incorporated into a point detonating fuse 10". Again, the concept of the present invention in the form of the modified embodiment of FIG. 5 may be applied equally as. well to proximity-actuated fuses or to time-actuated fuses. The structural components of the embodiment of FIG. 5 are identical to those shown in the embodiments of FIGS. 1, 2 and 4 and like elements have been given like numerical designations. However, in this particular embodiment a mechanical interconnecting mechanism is added to the fuse 10" between S and A device 21 and the second environment safety device 44. An inner body carries an axially shiftable inner firing pin (not shown) at its forward end, while the cylindrical casing section 12 carries within S and A cavity 20, an S and A device: 21 including rotor 22 having a through bore 26 in which is positioned, timer charge (not shown) at the forward end and detonator charge 30 at the rear end. Againfa latching hole may be provided on the peripheral surface of rotor 22 for latching or locking the rotor 22 into an axially aligned bore position once the rotor has rotated through angle A under a time-acceleration scheme at time T as shown in the plot of FIG. 3.

Further, the nose cylindrical portion 48 again moves rearwardly against the bias of compression spring 6-2 to cause cam surface 72, acting on cam follower edge 84, to move the slider 74 from its projected position of FIG. 5 to its recessed position of FIG. 6, against the bias of coil spring 88, whereupon slider hole 80 is axially aligned with hole 36 of transverse wall 34 and hole 82 of transverse wall 76. In like manner to the embodiment of FIG. 4, a detent mechanism 104 is carried at the rear end of S and A cavity 20 in which case, biasing spring 110 tends to force the tip end 114 of detent pin 108, rearwardly into detenting position.

Unlike the previous embodiments, however, in addition to a detent pin receiving opening or bore 102 extending inwardly from the side of the slider 74 there is also provided a second detent pin receiving bore 118 of identical diameter of identical size to bore 102 which also extends partially through the slider 74, parallel therewith and intermediate of bore 102 and the slider hole 80.

In this respect, the forward side 90 of the slider which abuts the rear of transverse wall 34, is provided with a longitudinal recess 120 which carries rectangular, slider plate 122. The recess 120 is formed within slider '74- such that the slider plate 182 is constrained to limited movement along a path which passes through the longitudinal axis of the fuse and at right angles thereto. Slider plate 122 is further provided with a transverse hole 124 which is equal in diameter to detent pin receiving bores 118 and 102 respectively. In addition to transverse side wall 34 carrying axial hole 36 and detent pin receiving hole 112 and counterbore 116, it is further provided with a rather large opening 126 intermediate hole 36 and counterbore 116. Hole 126 receives the projecting end 130 of a drive lever 132 which forms a part of the interconnecting mechanism mechanically coupling the S and A device 21 to the second environmental safety device 44.

In this respect, rotary drive lever 132 is mounted for rotation about the axis of mounting pin 136, the mounting pin with its axis parallel to but laterally offset from the pivot axis 24 of the S and A device rotor 22. Pin 136 is fixed within S and A cavity 20 and a biasing spring 138 has an end 140 carried by the pin slot and a free end 142 positioned within a narrow slot 144 on one side of the drive lever. The drive lever 132 is thus mounted for rotation about the axis of the mounting pin 136 and is spring biased for movement in a counterclockwise direction. The tip 146 of the narrow projecting end 130 passes completely through opening 126 in wall 34 and is received within a narrow slot 148 carried by the transversely movable slider plate 132. Further, the rotary drive lever 132 is provided with a contact surface 150 intermediate of the pivot pin 140 and tip 146, the con tact surface 150 being positioned in the path of the flat edge 152 of the S and A device rotor 22.

The arming elements of the fuse embodiment 10 are shown in FIG. as positioned prior to launch of the projectile. In a successful rocket launch for instance, with the addition of the interconnecting mechanism and the proper spring constants for spring 62, the actuation events are made to occur sequentially. In the embodiment of FIGS. 5 and 6 the second environment safety 44 must actuate prior to actuation of the first environment device 21 to achieve arming of the fuse, otherwise the fuse is safed. After rocket launch, the aerodynamic drag force which develops on the nose as a result of projectile velocity increase, compresses the coil spring 62 and moves the slider 74 to the hole alignment position without in any way disturbing the position of the drive lever biased slider plate 122 or the spring biased detent pin 108. The S and A device 21 actuates in response to time-acceleration with the last angular movement of the rotor mass 22 occurring with a snap action causing the flattened edge 152 of the rotor 22 to contact raised surface 150 of the rotary drive lever 132. This drives the rotary drive lever 132 clockwise against the bias of spring 138. The tip end of the lever 146- being received within recess 14-8 of the slider plate, imparts motion to the slider plate bringing hole 124 into alignment with detent pin tip 114, FIG. 6. At this moment, since the slider 74 has moved to its extreme contracted position against the bias of coil spring 88, bore hole 102 is opposite detent pin 108. Detent pin tip 114 is therefore spring driven through plate hole 124 into detent receiving hole 102 of the slider. This locks the slider 74 in the armed position and thus completes arming of the fuse by operation, first of the second environment safety device 44 and secondly in proper sequence the operation of the S and A or first environment safety device 21.

Should the opposite be true, that is, should the S and A device 21 complete its partial rotation through are A causing the spring biased rotary drive means to move the slider plate to a position where slide plate opening 124 is aligned with the detent pin tip 114, prior to actuation of the second environment safety device 44, the detent tip 114 will enter the aligned slider bore 118 to lock the slider 74 in its safe position preventing completion of fuse arming.

In a malfunction condition, for instance during ground handling of the fuse projectile, where the S and A device is inadvertently previously armed, the following events will occur. Should the S and A device actuate first, the slider plate hole 124 as mentioned previously will be driven into alignment with the detent pin 108 and the pin tip 114 will be spring driven into hole 118 to lock the slider 74 in the same position. Thus, even if aerodynamic drag force is applied or in ground handling if it is accidentally dropped on its nose, the second environment safety 44 will not move because it is locked in the safe position, thus safing the fuse.

From the above discussion, with respect to the third embodiment it is evident that the acceleration and aerodynamic characteristics of this embodiment are identical with those of the first two mechanisms. It is further evident that the two independent environments must be sensed in their proper respective levels by separate devices before the fuse can be armed. Further, each device is capable of safing the fuse in the event its environment is not proper, non-existent or not applied sufficiently long to cause detenting of each device. This double environment fuse provides for greater safety features than does the single environment fuse since two characteristics of successfully launched rockets must be sensed. In the concept found in the device of FIGS. 5 and 6, howeer, the sequence of actuation must occur with the second environment safety 44 actuating before the S and A device 21 otherwise the fuse becomes safed. In the proper actuation sequence, the fuse is armed and the mechanism detented or locked in the armed state.

With respect to all three embodiments, it is noted that the S and A device 21 is safe when the rotor detonators are out of line with the central fuse axis and armed when they are in line with the central fuse axis. The second environment safety device 44 is safe when in the uncompressed state, that is the slider holes do not align with the central fuse axis (blocking passage of explosive flash to the booster charge within cavity 38) and armed when the slider hole is in line with the fuse central axis. Further, while the concepts have been described with a rooket fired from the high or low velocity aircraft, the fuses of the present invention are applicable to any munition which is projected either by discharge from a launching vehicle or propelled by self-contained motors into fluid environments. This includes, but is not limited to rockets, mortars, hand grenades, bombs and torpedoes. Further, while the materials for the different elements of the improved fuses, have not been described the elements are constructed from conventional materials which may include but are not limited to metal, plastic etc.

While the invention has been particularly shown and described with reference topreferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a projectile fusing system including: an integrating accelerometer carrying a detonator charge and movable from a first, non-detonating position to a second, detonating position relative to a projectile carried warhead charge, the improvement comprising: a movable, low mass member carried by said projectile and subjected to aerodynamic drag during projectile flight, means for biasing said low mass member to a first position, means coupled to said low mass member for operatively isolating said accelerometer carried detonator charge from said warhead charge when said low mass member is in said first position, a longitudinal passage position between said detonator charge and said warhead charge, said means coupled to said low mass member for operatively isolating said accelerometer carried detonator charge from said warhead charge when said low mass member is in a first position comprising a slider movably carried by said projectile for movement from a first passage blocking position to a second passage non-blocking position, whereby; attainment of projectile velocity of a predetermined magnitude causes said low mass member to overcome its bias to operatively expose said warhead charge to said detonator charge.

2. The fusing system as claimed in claim 1 wherein said integrating accelerometer comprises a rotor pivotally mounted for movement from a first to a second position, a bore carried by said rotor for receiving said detonator charge and a firing pin carried by said projectile in alignment with said longitudinal passage whereby, upon sustained acceleration said rotor moves from a first nonalignment position to a second position wherein said charge carrying bore, said firing pin and said longitudinal passage are in series and in axial alignment.

3. The fusing system as claimed in claim ll wherein said projectile fuse includes an inner cylindrical member, and said movable low mass member comprises; an outer cylindrical member having a nose portion overlying the front end of said inner cylindrical member and spaced therefrom, means for slidably mounting said outer cylindrical member on said inner cylindrical member, and means for spring biasing said outer cylindrical member forwardly from said inner cylindrical member.

4. The fusing system as claimed in claim 3 further comprising; cam means carried by said outer cylindrical member, cam follower means carried by said slider and means for biasing said cam follower into contact with said cam means.

5. The fusing system as claimed in claim 1 further comprising a detent mechanism for locking said slider in passive non-blocking position.

6. The fusing system as claimed in claim 4 further including spaced transversely extending side walls carried by said inner cylindrical member to form a transverse slider passage and wherein said slider biasing means comprises a coil spring positioned between the inner end of said slider and said inner cylindrical member.

7. The fusing system as claimed in claim 4 wherein said longitudinal passage is formed by holes carried respectively by said transverse side walls and said transversely movable slider.

8. The fusing system as claimed in claim 7 further including; a detent mechanism for locking said slider in non-passage blocking position, said detent mechanism comprising a spring biased detent piston carried within one of said transverse walls, and a detent pin receiving hole carried by said slider.

9. The fusing system as claimed in claim 1 further including means responsive to movement of said integrating accelerometer from a first non-detonating to a second detonating position for preventing subsequent movement of said low mass second environment member from its charge isolating position.

10. The fusing system as claimed in claim 6 further including a spring biased detent pin carried by said projectile for movement into the path of said transversely movable slider, and first and second detent holes carried by said slider, a movable slider plate for selectively preventing movement of said detent pin into said detent pin receiving holes and means responsive to movement of said integrating accelerometer from said first non-detonat ing position to said second detonating position for controlling the position of said slider plate.

11. The fusing system as claimed in claim 10 wherein: said integrating accelerometer comprises a pivotable rotor carried by said projectile for movement to an axial bore hole alignment position with respect to said longitudinal passage, said slider plate is carried by said fuse and movable between a detent pin blocking and a detent pin nonblocking position, and said system futher includes a drive lever pivotably carried by said fuse and operatively coupled to said slider plate, biasing means for biasing said drive lever and said slider plate into detent pin blocking position and means carried by said drive lever and responsive to pivoting of said rotor into bore alignment position for forcing said drive lever to move said slider plate into non-pin blocking position whereby, said detent pin is received by one of said slider detent pin receiving holes.

12. In a projectile fusing system including an integrating accelerometer carrying a detonator charge and movable from a first, non-detonating position to a second, detonating position relative to a projectile carried warhead charge, the improvement comprising: a movable member carried by said projectile and subjected to velocity effects during projectile flight, means for biasing said movable member to a first position, means coupled to said member for operatively isolating said accelerometer carrying said detonator charge from said warhead charge when said movable member is in said first position, a longitudinal passage poitioned between said detonator charge and said warhead charge, with said means operatively coupled to said movable member comprising: a slider movably carried by said projectile for movement from a first passage blocking position to a second non-blocking position, and wherein said projectile fuse includes an inner cylindrical member, said movable member cornpirsing an outer cylindrical member having a nose portion overlying the front end of said inner cylindrical member and spaced therefrom, means for slidably mounting said outer cylindrical member on said inner cylindrical member, means for spring biasing said outer cylindrical member forwardly relative to said inner cylindrical member, cam means carried by said cylindrical member and cam follower means carried by said slider and means for biasing said cam follower into contact with said cam means, whereby attainment of projectile velocity of a predetermined magnitude causes said movable member to overcome its bias to operatively expose said warhead charge to said deto nator charge.

13. The fusing system as claimed in claim 12, further including spaced transversely extending side walls carried by said inner cylindrical member to form a transverse slider passage and wherein said slider biasing means comprises a coil spring positioned between the inner end of said slider and said cylindrical member.

14. The fusing system as claimed in claim 12, wherein said longitudinal passage is formed by holes carried respectively by said transverse side walls and said transversely movable slider.

15. The fusing system as claimed in claim 14, further including a detent mechanism for locking said slider in non-passage blocking position, said detent mechanism comprising a spring biased detent piston carried within one of said transverse walls, and a detent pin receiving hole carried by said slot.

16. The fusing system as claimed in claim 13, further including a spring biased detent pin carried by said projectile for movement into the path of said transversely movable slider, and first and second detent holes carried by said slider, a movable slider plate for selectively preventing movement of said detent pin into said detent pin receiving hole and means responsive to movement of integrating accelerometer from said first non-detonating position to said second detonating position for controlling the position of said slider plate.

17. The fusing system as claimed in claim 16, wherein: said integrating accelerometer comprises a pivotable rotor carried by said projectile for movement to an axial bore 1 1 hole alignment position with respect to said longitudinal passage, said slider plate is carried by said fuse and movable between a detent pin blocking and a detent pin non-blocking position, and said system further includes a drive lever pivotably carried by said fuse and operatively coupled to said slider plate, biasing means for biasing said drive lever and said slider plate in detent pin blocking position and means carried by said drive lever and response to pivoting of said rotary into bore alignment position for forcing said drive lever to move said slider plate into pin non-blocking position, whereby said detent pin is received by one of said slider detent pin receiving holes.

References Cited BENJAMIN A. BORCHELT, Primary Examiner 10 I. J. DEVITT, Assistant Examiner US. Cl. X.R. 

